Revert "Make symfony/security-acl as a suggestion"

This reverts commit a0a3157.
Do not pretend ACLs are optional when they are really not. The admin
class implements an interface from the ACL package. This means that
anyone that uses an admin (so any user of the package, really), needs
to have that interface (and the ACL package).
Fixes #3511

Resources/doc/reference/installation.rst

@@ -21,10 +21,6 @@ for older versions:
 
     Please provide a version constraint for the sonata-project/admin-bundle requirement: dev-master
 
-.. note::
-
-    If you are using Symfony 2.8 and upper, you need to require :code:`symfony/security-acl` to make it working.
-
 Selecting and downloading a storage bundle
 ------------------------------------------
 

composer.json

@@ -30,6 +30,7 @@
         "symfony/translation":"~2.3|~3.0",
         "symfony/dependency-injection": "~2.3,>=2.3.3|~3.0",
         "symfony/property-access": "~2.3|~3.0",
+        "symfony/security-acl": "~2.3|~3.0",
         "twig/twig": "~1.23",
         "twig/extensions": "~1.0",
         "sonata-project/exporter": "~1.0",
@@ -42,15 +43,13 @@
     "require-dev": {
         "sensio/generator-bundle": "~2.3|~3.0",
         "symfony/yaml": "~2.3|~3.0",
-        "symfony/security-acl": "~2.4|~3.0",
         "sonata-project/intl-bundle": "dev-master",
         "symfony/phpunit-bridge": "~2.7|~3.0"
     },
     "suggest": {
         "jms/translation-bundle": "Extract message keys from Admins",
         "sensio/generator-bundle": "Add sonata:admin:generate command",
-        "sonata-project/intl-bundle": "Add localized date and number into the list",
-        "symfony/security-acl": "To make sonata working with Symfony >=2.8"
+        "sonata-project/intl-bundle": "Add localized date and number into the list"
     },
     "autoload": {
         "psr-4": { "Sonata\\AdminBundle\\": "" }